<?php
/*
 *  $Id: Oracle.php 7490 2010-03-29 19:53:27Z jwage $
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.doctrine-project.org>.
 */

/**
 * Doctrine_Expression_Sqlite
 *
 * @package     Doctrine
 * @subpackage  Expression
 * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
 * @link        www.doctrine-project.org
 * @since       1.0
 * @version     $Revision: 7490 $
 * @author      Konsta Vesterinen <kvesteri@cc.hut.fi>
 */
class Doctrine_Expression_Oracle extends Doctrine_Expression_Driver
{
	/**
	 * Returns a series of strings concatinated
	 *
	 * concat() accepts an arbitrary number of parameters. Each parameter
	 * must contain an expression
	 *
	 * @param string $arg1, $arg2 ... $argN     strings that will be concatinated.
	 * @return string
	 */
	public function concat()
	{
		$args = func_get_args();

		return join(' || ' , $args);
	}

	/**
	 * return string to call a function to get a substring inside an SQL statement
	 *
	 * Note: Not SQL92, but common functionality.
	 *
	 * @param string $value         an sql string literal or column name/alias
	 * @param integer $position     where to start the substring portion
	 * @param integer $length       the substring portion length
	 * @return string               SQL substring function with given parameters
	 */
	public function substring($value, $position, $length = null)
	{
		if ($length !== null)
		return "SUBSTR($value, $position, $length)";

		return "SUBSTR($value, $position)";
	}

	/**
	 * Return string to call a variable with the current timestamp inside an SQL statement
	 * There are three special variables for current date and time:
	 * - CURRENT_TIMESTAMP (date and time, TIMESTAMP type)
	 * - CURRENT_DATE (date, DATE type)
	 * - CURRENT_TIME (time, TIME type)
	 *
	 * @return string to call a variable with the current timestamp
	 */
	public function now($type = 'timestamp')
	{
		switch ($type) {
			case 'date':
			case 'time':
			case 'timestamp':
			default:
				return 'TO_CHAR(CURRENT_TIMESTAMP, \'YYYY-MM-DD HH24:MI:SS\')';
		}
	}

	/**
	 * random
	 *
	 * @return string           an oracle SQL string that generates a float between 0 and 1
	 */
	public function random()
	{
		return 'dbms_random.value';
	}

	/**
	 * Returns global unique identifier
	 *
	 * @return string to get global unique identifier
	 */
	public function guid()
	{
		return 'SYS_GUID()';
	}
}